Handle OpenSSL.SSL.WantReadError and WantWriteError in pyopenssl adapter

cheroot/makefile.py

@@ -24,13 +24,22 @@ def write(self, b):
             self._flush_unlocked()
             return len(b)
 
+    def _safe_call(self, is_reader, call, *args, **kwargs):
+        """Call the supplied callable with retries, as needed.
+
+        Method to be overridden in subclasses/mix-ins.
+        """
+        return call(*args, **kwargs)
+
     def _flush_unlocked(self):
         self._checkClosed('flush of closed file')
         while self._write_buf:
             try:
                 # ssl sockets only except 'bytes', not bytearrays
                 # so perhaps we should conditionally wrap this for perf?
-                n = self.raw.write(bytes(self._write_buf))
+                n = self._safe_call(
+                    False, self.raw.write, bytes(self._write_buf),
+                )
             except io.BlockingIOError as e:
                 n = e.characters_written
             del self._write_buf[:n]

cheroot/ssl/pyopenssl.py

@@ -145,6 +145,14 @@ def readline(self, size=-1):
             size,
         )
 
+    def read(self, *args, **kwargs):
+        """Read from the wrapped socket."""
+        return self._safe_call(
+            True,
+            super(SSLFileobjectMixin, self).read,
+            *args, **kwargs
+        )
+
     def sendall(self, *args, **kwargs):
         """Send whole message to the socket."""
         return self._safe_call(